Photovoltaic cells for a portable electronic device

ABSTRACT

Systems and methods for generating electrical current from at least one photovoltaic cell is described herein. The photovoltaic cell may be disposed over a display of an electronic device. The photovoltaic cell may comprise first and second conductive layers and a photovoltaic layer. The first conductive layer may be etched such that a width of the metal layer is less than a width of the photovoltaic layer providing visibility to the display disposed below. In some embodiments, a capacitive touch sensor is disposed between the metal layer and the absorber layer for providing interaction with a user.

RELATED APPLICATIONS

This non-provisional patent application is a continuation of U.S. patentapplication Ser. No. 17/203,996, filed Mar. 17, 2021, and entitled“IMPROVED PHOTOVOLTAIC CELLS FOR A PORTABLE ELECTRONIC DEVICE,” which inturn claims priority benefit, with regard to all common subject matter,of earlier-filed U.S. Provisional Patent Application No. 62/992,517,filed Mar. 20, 2020, and entitled “IMPROVED PHOTOVOLTAIC.” Theidentified earlier-filed patent applications are hereby incorporated byreference in their entirety into the present application.

BACKGROUND

Conventional wearable electronic devices, like smartwatches, GPSnavigation devices, fitness trackers, etc. utilize touchscreens toprovide a user interface to users of the electronic devices. Batterylife is important for these devices as space is limited. The battery mayneed to be charged on a regular basis and it can be aggravating forusers to stop wearing a device for recharging. Some attempts have beenmade to equip smartwatches with semitransparent solar panels such as byusing a discrete solar cell positioned on top of (or over) the watch'sdisplay. Typically, this leads to decreased visibility or inefficiencyof the system. Typically, the solar cells are disposed over the displaythus limiting visibility to the display. This can be distracting for theuser and is not aesthetically pleasing.

SUMMARY

Embodiments of the present invention provide a first embodiment directedto a photovoltaic power system for an electronic device, thephotovoltaic power system comprising at least one photovoltaic cellcomprising a first layer comprising a first conductive electrode, and asecond layer electrically connected to the first layer and configured togenerate electrical current when exposed to electromagnetic radiation,and a third layer comprising a second conductive electrode, wherein afirst layer width is less than a second layer width.

A second embodiment is directed to a photovoltaic power system for anelectronic device, the photovoltaic power system comprising a base layercomprising a touch sensor, at least one photovoltaic cell comprising afirst layer comprising a first conductive electrode, and a second layerelectrically connected to the first layer and configured to generateelectrical current when exposed to electromagnetic radiation, and athird layer comprising a second conductive electrode, wherein a firstlayer width is less than a second layer width.

A third embodiment is directed to a photovoltaic power system for anelectronic device, the photovoltaic power system comprising a base layercomprising at least one photovoltaic cell comprising a first layercomprising a first conductive electrode, and a second layer electricallyconnected to the first layer and configured to generate electricalcurrent when exposed to electromagnetic radiation, a third layercomprising a second conductive electrode, wherein a first layer width isless than a second layer width, and at least one exterior photovoltaiccell disposed along a perimeter of the base layer.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Other aspectsand advantages of the invention will be apparent from the followingdetailed description of the embodiments and the accompanying drawingfigures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Embodiments of the invention are described in detail below withreference to the attached drawing figures, wherein:

FIG. 1 depicts an exemplary electronic device for use with theembodiments of the invention;

FIG. 2 depicts an exemplary hardware system for use with embodiments ofthe invention;

FIG. 3 depicts an exemplary embodiment of a various layers of anenergy-collecting touchscreen unit;

FIG. 4 depicts a table presenting embodiments of various photovoltaiccell designs;

FIGS. 5A-5B depict an exemplary process of producing the photovoltaiccells of FIG. 4 ;

FIGS. 6 and 7 depict a touch sensor on a front face of the common baselayer; and

FIGS. 8 and 9 depict a photovoltaic surface comprising photovoltaiccells on a face of the common base layer of FIGS. 6 and 7 .

The drawing figures do not limit the invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the invention.

DETAILED DESCRIPTION

The following detailed description references the accompanying drawingsthat illustrate specific embodiments in which the invention can bepracticed. The embodiments are intended to describe aspects of theinvention in sufficient detail to enable those skilled in the art topractice the invention. Other embodiments can be utilized and changescan be made without departing from the scope of the invention. Thefollowing detailed description is, therefore, not to be taken in alimiting sense. The scope of the invention is defined only by theappended claims, along with the full scope of equivalents to which suchclaims are entitled.

In this description, references to “one embodiment,” “an embodiment,” or“embodiments” mean that the feature or features being referred to areincluded in at least one embodiment of the technology. Separatereferences to “one embodiment,” “an embodiment,” or “embodiments” inthis description do not necessarily refer to the same embodiment and arealso not mutually exclusive unless so stated and/or except as will bereadily apparent to those skilled in the art from the description. Forexample, a feature, structure, act, etc. described in one embodiment mayalso be included in other embodiments but is not necessarily included.Thus, the technology can include a variety of combinations and/orintegrations of the embodiments described herein.

In general, embodiments of the invention are directed to systems andmethods for providing improved photovoltaic cells that suitable for usein connection with an electronic device. The photovoltaic cells may beprovided such that they have low visibility to a user yet are exposed toelectromagnetic radiation and are sufficiently efficient to providenecessary power to run the electronic device. The photovoltaic cells maybe configured to reduce visibility of the photovoltaic cell componentsto the user while increasing visibility of a display disposed behind thephotovoltaic cells relative to the user. Typically, an electrode of aphotovoltaic cell may be visible. In some configurations of the presentinvention, a photovoltaic stack may be provided in which the width of ametal electrode is less than the width of absorber layers for example,p-type, intrinsic, n-type (PIN) and less than the width of a transparentconductive oxide (TCO) layer such as aluminum-doped zinc oxide (AZO)layers. As the metal electrode is largely responsible for the lack oftransparency in the photovoltaic stack, increasing the width of theabsorber layers in comparison to the width of the metal electrodeimproves energy performance while providing similar, or even better,optical transparency. That is, the appearance of a transparentphotovoltaic cell may be improved by decreasing the width of the metalelectrode without decreasing the width of the absorber layer(s). Thisconfiguration may be used with single-cell photovoltaic implementationsor with multi-cell photovoltaic implementations as described inconnection with certain embodiments below.

Further, the photovoltaic cells may be disposed on the electronic devicein such a way as to present low visibility while maintaining exposure toelectromagnetic radiation. For example, the photovoltaic cells may beexposed around an outer edge of a display or in a specific patternacross a display of a portable electronic device. The specific patternused, and the location of the photovoltaic cells may increasetransparency while maintaining a high level of power generation.

Embodiments of the present invention may be employed with anyphotovoltaic cell configuration, such as for example, the configurationsdescribed in U.S. Patent Application Publication No. US20160126407A1,which is incorporated herein by specific reference. That is, differingelectrode widths and absorber widths may be employed with any cellarrangement and not just the example arrangements illustrated herein.Additionally, absorbers of any configuration may be employed byembodiments of the present invention without limitation to theillustrated examples described herein.

Exemplary Environment

FIG. 1 depicts a perspective view of a mobile electronic device (in thisembodiment, a smartwatch 100) in accordance with one or more embodimentsof the present disclosure. The photovoltaic cells, described below, maybe configured to be disposed in, and power, the mobile electronicdevice. The exemplary smartwatch 100 may be operable to provide fitnessinformation and/or navigation functionality to a user of the smartwatch100. The smartwatch 100 may be configured in a variety of ways. Forinstance, the smartwatch 100 may be configured for use during fitnessand/or sporting activities and comprise a cycle computer, a sport watch,a golf computer, a smart phone providing fitness or sportingapplications (apps), a handheld GPS device used for hiking, and soforth. However, it is contemplated that the present teachings can beimplemented in connection with any mobile electronic device. Thus, themobile electronic device may also be configured as a portable navigationdevice (PND), a mobile phone, a handheld portable computer, a tabletcomputer, a personal digital assistant, a multimedia device, a mediaplayer, a game device, combinations thereof, and so forth. In thefollowing description, a referenced component, such as mobile electronicdevice or specifically, smartwatch 100, may refer to one or moreentities, and therefore by convention reference may be made to a singleentity (e.g., the smartwatch 100) or multiple entities (e.g., thesmartwatches 100, the plurality of smartwatches 100, and so on) usingthe same reference number. In some embodiments, the photovoltaic cellsmay provide power to run all components of the mobile electronic device.

The smartwatch 100 includes a housing 102. The housing 102 is configuredto house, e.g., substantially enclose, various components of thesmartwatch 100. The housing 102 may be formed from a lightweight andimpact-resistant material such as metal or a metal alloy, plastic,nylon, or combinations thereof, for example. The housing 102 may beformed from a non-conductive material, such a non-metal material, forexample. The housing 102 may include one or more gaskets, e.g., a seal,to make it substantially waterproof or water resistant. The housing 102may include a location for a battery and/or another power source forpowering one or more components of the smartwatch 100. The housing 102may be a singular piece or may include a plurality of sections. Inembodiments, the housing 102 may be formed from a conductive material,such as metal, or a semi-conductive material.

In various embodiments, the smartwatch 100 includes a viewing area 104.The viewing area 104 may include a liquid crystal display (LCD), a thinfilm transistor (TFT), a light-emitting diode (LED), a light-emittingpolymer (LEP), and/or a polymer light-emitting diode (PLED). However,embodiments are not so limited. In various embodiments, the viewing area104 includes one or more analog or mechanical presentation indicators,such as analog watch hands or mechanical complications or othermechanical gauge or dial indicators. In these embodiments, the viewingarea 104 is used to display text and/or graphical information. Theviewing area 104 may be backlit such that it may be viewed in the darkor other low-light environments. However, embodiments are not solimited. The viewing area 104 may be enclosed by a transparent lens orcover layer that covers and/or protects components of the smartwatch100. The viewing area 104 may be backlit via a backlight such that itmay be viewed in the dark or other low-light environments. The viewingarea 104 may be provided with a touch screen to receive input (e.g.,data, commands, etc.) from a user. For example, a user may operate thesmartwatch 100 by touching the touch screen and/or by performinggestures on the screen. In some embodiments, the touch screen may be acapacitive touch screen, a resistive touch screen, an infrared touchscreen, combinations thereof, and the like. The smartwatch 100 mayfurther include one or more input/output (I/O) devices (e.g., a keypad,buttons, a wireless input device, a thumbwheel input device, atrackstick input device, and so on). The I/O devices may include one ormore audio I/O devices, such as a microphone, speakers, and so on.

As noted above, in various embodiments, the smartwatch 100 includes oneor more mechanical watch hands (e.g., hour hand, minute hand, secondhand, and so on) or mechanical complications (date, calendar, dialindicator, and so on). These mechanical watch hands or mechanicalcomplications may be driven by electric motors or other mechanicalstructures (e.g., spring, wheel, and so on).

The smartwatch 100 may also include a communication modulerepresentative of communication functionality to permit smartwatch 100to send/receive data between different devices (e.g.,components/peripherals) and/or over the one or more networks. Thecommunication module may be representative of a variety of communicationcomponents and functionality including, but not limited to: one or moreantennas; a browser; a transmitter and/or receiver; a wireless radio;data ports; software interfaces and drivers; networking interfaces; dataprocessing components; and so forth. The smartwatch 100 may beconfigured to communicate via one or more networks with a cellularprovider and an Internet provider to receive mobile phone service andvarious content, respectively. Content may represent a variety ofdifferent content, examples of which include, but are not limited to:map data, which may include route information; web pages; services;music; photographs; video; email service; instant messaging; devicedrivers; real-time and/or historical weather data; instruction updates;and so forth.

The one or more networks are representative of a variety of differentcommunication pathways and network connections which may be employed,individually or in combinations, to communicate among variouscomponents. Thus, the one or more networks may be representative ofcommunication pathways achieved using a single network or multiplenetworks. Further, the one or more networks are representative of avariety of different types of networks and connections that arecontemplated including, but not limited to: The Internet; an intranet; asatellite network; a cellular network; a mobile data network; wiredand/or wireless connections; and so forth. Examples of wireless networksinclude but are not limited to: networks configured for communicationsaccording to: one or more standard of the Institute of Electrical andElectronics Engineers (IEEE), such as 802.11 or 802.16 (Wi-Max)standards; Wi-Fi standards promulgated by the Wi-Fi Alliance; Bluetoothstandards promulgated by the Bluetooth Special Interest Group; and soon. Wired communications are also contemplated such as through universalserial bus (USB), Ethernet, serial connections, and so forth.

In accordance with one or more embodiments of the present disclosure,the smartwatch 100 includes a control button 106. As illustrated in FIG.1 , the control button 106 is associated with, e.g., adjacent to, thehousing 102. While FIG. 1 illustrates four control buttons 106associated with the housing 102, embodiments are not so limited. Forexample, the smartwatch 100 may include fewer than four control buttons106, such as one, two, or three control buttons. Additionally, thesmartwatch 100 may include more than four control buttons 106, such asfive, six, or seven, for example. The control button 106 is configuredto control a function of the smartwatch 100. In various embodiments,regions of the viewing area of the smartwatch 100 are covered with atouch sensor as further described below in connection with FIGS. 3-9 .In these embodiments, a touchscreen functions as a user interfacecomponent to provide input to the smartwatch 100, when a user touchesvarious surface regions of the touchscreen associated with thesmartwatch 100, which regions are configured to control a function ofthe smartwatch 100.

Functions of the smartwatch 100 may be associated with a locationdetermining component 202 (FIG. 2 ) and/or a performance monitoringcomponent 204 (FIG. 2 ). Functions of the smartwatch 100 may include,but are not limited to, displaying a current geographic location of thesmartwatch 100, mapping a location in the viewing area 104, locating adesired location and displaying the desired location on the viewing area104, monitoring a user's heart rate, monitoring a user's speed,monitoring a distance traveled, calculating calories burned, and thelike. In embodiments, user input may be provided from movement of thehousing 102. For example, an accelerometer may be used to identify tapinputs on the housing 102 or upward and/or sideways movements of thehousing 102. In embodiments, user input may be provided from touchinputs identified using various touch sensing technologies, such asresistive touch or capacitive touch interfaces.

In accordance with one or more embodiments of the present disclosure,the smartwatch 100 includes a strap 108. As illustrated in FIG. 1 , thestrap 108 is associated with, e.g., coupled to, the housing 102. Forexample, the strap 108 may be removably secured to the housing 102 viaattachment of securing elements to corresponding connecting elements.Examples of securing elements and/or connecting elements include, butare not limited to hooks, latches, clamps, snaps, and the like. Thestrap 108 may be made of a lightweight and resilient thermoplasticelastomer and/or a fabric, for example, such that the strap 108 mayencircle a portion of a user without discomfort while securing thehousing 102 to the user. The strap 108 may be configured to attach tovarious portions of a user, such as a user's leg, waist, wrist, forearm,and/or upper arm.

FIG. 2 shows a block diagram 200 of the internal components of anexemplary mobile electronic device such as the smartwatch 100 of FIG. 1, in accordance with various embodiments of the present disclosure. Thehousing 102 can include a location determining component 202 positionedwithin the housing. For example, the location determining component 202may include an antenna 206 having a ground plane. The ground plane maybe formed by coupling a printed circuit board and/or a conductive cagewith the antenna 206. The antenna 206 and the ground plane may becoupled using solder, connection elements, or combinations thereof.

The location determining component 202 may be a GPS receiver that isconfigured to provide geographic location information of the watch. Thelocation determining component 202 may be, for example, a GPS receiversuch as those provided in various products by GARMIN®. Generally, GPS isa satellite-based radio navigation system capable of determiningcontinuous position, velocity, time, and direction information. Multipleusers may simultaneously utilize GPS. GPS incorporates a plurality ofGPS satellites that orbit the earth. Based on these orbits, GPSsatellites can relay their location to a GPS receiver. For example, uponreceiving a GPS signal, e.g., a radio signal, from a GPS satellite, thewatch disclosed herein can determine a location of that satellite. Thewatch can continue scanning for GPS signals until it has acquired anumber, e.g., at least three, of different GPS satellite signals. Thewatch may employ geometrical triangulation, e.g., where the watchutilizes the known GPS satellite positions to determine a position ofthe watch relative to the GPS satellites. Geographic locationinformation and/or velocity information can be updated, e.g., in realtime on a continuous basis, for the watch.

The location determining component 202 may also be configured to providea variety of other position-determining functionality. Locationdetermining functionality, for purposes of discussion herein, may relateto a variety of different navigation techniques and other techniquesthat may be supported by “knowing” one or more positions. For instance,location determining functionality may be employed to provideposition/location information, timing information, speed information,and a variety of other navigation-related data. Accordingly, thelocation determining component 202 may be configured in a variety ofways to perform a wide variety of functions. For example, the locationdetermining component 202 may be configured for outdoor navigation,vehicle navigation, aerial navigation (e.g., for airplanes,helicopters), marine navigation, personal use (e.g., as a part offitness-related equipment), and so forth. Accordingly, the locationdetermining component 202 may include a variety of devices to determineposition using one or more of the techniques previously described.

The location determining component 202, for instance, may use signaldata received via a GPS receiver in combination with map data that isstored in the memory to generate navigation instructions (e.g.,turn-by-turn instructions to an input destination or point of interest),show a current position on a map, and so on. Location determiningcomponent 202 may include one or more antennas 206 to receive signaldata as well as to perform other communications, such as communicationvia one or more networks. The location determining component 202 mayalso provide other positioning functionality, such as to determine anaverage speed, calculate an arrival time, and so on.

The location determining component 202 may include one or moreprocessors, controllers, and/or other computing devices as well as amemory 208, e.g., for storing information accessed and/or generated bythe processors or other computing devices. The processor may beelectrically coupled with a printed circuit board and operable toprocess position determining signals received by the antenna 206. Thelocation determining component 202, e.g., the antenna 206, is configuredto receive position determining signals, such as GPS signals from GPSsatellites, to determine a current geographic location of the watch. Thelocation determining component 202 may also be configured to calculate aroute to a desired location, provide instructions, e.g., directions, tonavigate to the desired location, display maps and other information onthe display, and to execute other functions, such as, but not limitedto, those functions described herein.

The memory 208 may store cartographic data and routing used by orgenerated by the location determining component 202. The memory 208 maybe integral with the location determining component 202, stand-alonememory, or a combination of both. The memory 208 may include, forexample, a removable nonvolatile memory card, such as a TransFlash card.The memory 208 is an example of device-readable storage media thatprovides storage functionality to store various data associated with theoperation of the smartwatch 100, such as the software program and codesegments mentioned above, or other data to instruct the processor andother elements of the smartwatch 100 to perform the techniques describedherein. A wide variety of types and combinations of memory may beemployed. The memory 208 may be integral with the processor, stand-alonememory, or a combination of both. The memory 208 may include, forexample, removable and non-removable memory elements such as RAM, ROM,Flash (e.g., SD Card, mini-SD card, micro-SD Card), magnetic, optical,USB memory devices, and so forth.

The antenna 206, for example, may be configured to receive and/ortransmit a signal, such as a GPS signal. Antenna 206 may be any antennacapable of receiving wireless signals from a remote source, includingdirectional antennas and omnidirectional antennas. Antenna 206 mayinclude any type of antennas in which the length of the ground planeaffects the efficiency of the antenna 206. In accordance with one ormore embodiments of the present disclosure, the antenna 206 is anomnidirectional antenna having a ground plane. An omnidirectionalantenna may receive and/or transmit in both orthogonal polarizations,depending upon direction. In other words, omnidirectional antennas donot have a predominant direction of reception and/or transmission.Examples of omnidirectional antennas include, but are not limited to,inverted-F antennas (IFAs) and planar inverted-F antennas (PIFAs). Incontrast to omnidirectional antennas, directional antennas have aprimary lobe of reception and/or transmission over an approximate 70 by70-degree sector in a direction away from the ground plane. Examples ofdirectional antennas include, but are not limited to, microstripantennas and patch antennas.

In accordance with one or more embodiments of the present disclosure,the antenna 206 may be an embedded antenna. As used herein, an embeddedantenna refers to an antenna that is positioned completely within adevice housing. For example, the antenna 206 may be positionedcompletely within the housing 102. In some embodiments, the antenna 206may be an external antenna with all or a portion of the antenna 206exposed from the housing 102.

As discussed, the location determining component 202 includes theantenna 206. The antenna 206 may be associated with, e.g., formed onand/or within, an antenna support assembly. Alternatively, the antenna206 may be positioned on a top portion or one or more side portions ofthe antenna support assembly.

The printed circuit board may support a number of processors,microprocessors, controllers, microcontrollers, programmable intelligentcomputers (PIC), field-programmable gate arrays (FPGA), other processingcomponents, other field logic devices, application specific integratedcircuits (ASIC), and/or the memory 208 that is configured to accessand/or store information that is received or generated by the watch. Thesmartwatch 100 may implement one or more software programs to controltext and/or graphical information on the display, as discussed herein.As an example, the printed circuit board may support the bottom portionof the antenna support assembly. In some embodiments, the antennasupport assembly and antenna 206 may be positioned in the center of thetop surface, bottom surface, or to a side of the of the printed circuitboard.

A processor 210 may provide processing functionality for the smartwatch100 and may include any number of processors, micro-controllers, orother processing systems, and resident or external memory for storingdata and other information accessed or generated by the smartwatch 100.The processor 210 may execute one or more software programs thatimplement the techniques and modules described herein. The processor 210is not limited by the materials from which it is formed, or theprocessing mechanisms employed therein and, as such, may be implementedvia semiconductor(s) and/or transistors (e.g., electronic integratedcircuits (ICs)), and so forth.

In accordance with one or more embodiments of the present disclosure,functions of the smartwatch 100 may be associated with the locationdetermining component 202 and/or the performance monitoring component204. For example, the location determining component 202 is configuredto receive signals, e.g., position determining signals, such as GPSsignals, to determine a position of the watch as a function of thesignals. The location determining component 202 may also be configuredto calculate a route to a desired location, provide instructions tonavigate to the desired location, display maps and/or other informationin the viewing area 104, to execute other functions described herein,among other things.

The performance monitoring component 204 may be positioned within thehousing 102 and be coupled to the location determining component 202 andthe viewing area 104. The performance monitoring component 204 mayreceive information, including, but not limited to geographic locationinformation, from the location determining component 202, to perform afunction, such as monitoring performance and/or calculating performancevalues and/or information related to a watch user's movement, e.g.,exercise. The monitoring of the performance and/or the calculatingperformance values may be based at least in part on the geographiclocation information. The performance values may include, for example, auser's heart rate, speed, a total distance traveled, total distancegoals, speed goals, pace, cadence, and calories burned. These valuesand/or information may be presented in the viewing area 104.

In embodiments, the smartwatch 100 includes a user interface, which isstorable in the memory 208 and executable by the processor 210. The userinterface is representative of functionality to control the display ofinformation and data to the user of the smartwatch 100 in the viewingarea 104. In some implementations, a display module within the viewingarea 104 may not be integrated into the smartwatch and may instead beconnected externally using universal serial bus (USB), Ethernet, serialconnections, and so forth. The user interface may provide functionalityto allow the user to interact with one or more applications of thesmartwatch 100 by providing inputs via the touch screen and/or the I/Odevices. For example, the user interface may cause an applicationprogramming interface (API) to be generated to expose functionality toan application to configure the application for display in the viewingarea 104 or in combination with another display. In embodiments, the APImay further expose functionality to configure the application to allowthe user to interact with an application by providing inputs via thetouch screen and/or the I/O devices. Applications may comprise software,which is storable in the memory 208 and executable by the processor 210,to perform a specific operation or group of operations to furnishfunctionality to the smartwatch 100. Example applications may includefitness application, exercise applications, health applications, dietapplications, cellular telephone applications, instant messagingapplications, email applications, photograph sharing applications,calendar applications, address book applications, and so forth.

In various embodiments, the user interface may include a browser. Thebrowser enables the smartwatch 100 to display and interact with contentsuch as a webpage within the World Wide Web, a webpage provided by a webserver in a private network, and so forth. The browser may be configuredin a variety of ways. For example, the browser may be configured as anapplication accessed by the user interface. The browser may be a webbrowser suitable for use by a full resource device with substantialmemory and processor resources (e.g., a smart phone, a personal digitalassistant (PDA), etc.). However, in one or more implementations, thebrowser may be a mobile browser suitable for use by a low-resourcedevice with limited memory and/or processing resources (e.g., a mobiletelephone, a portable music device, a transportable entertainmentdevice, wristband, etc.). Such mobile browsers typically conservebattery energy, memory and processor resources, but may offer fewerbrowser functions than web browsers.

In various embodiments, the smartwatch 100 includes an energy storagedevice such as a battery 212. It is understood that this energy storagedevice could employ any conventional or later developed energy storageor chemical battery technology, such as a supercapacitor, for exampleemploying electrostatic double-layer capacitance and electrochemicalpseudocapacitance. In various embodiments the energy storage device orbattery 212 includes a lithium polymer battery. As explained inconnection with FIG. 1 , in various embodiments, the control button 106is configured to control a function of the smartwatch 100.

In some embodiments, the energy storage device is electrically connectedto the photovoltaic cells described herein. The photovoltaic cells mayprovide power to charge the energy storage device. The photovoltaiccells may be connected directly to the energy storage device or throughan intermediate processor for balancing the charge across a plurality ofbattery cells.

FIG. 3 illustrates the various layers of an energy-collectingtouchscreen unit 300 in accordance with an embodiment of the presentdisclosure. In various embodiments, a thin, substantially transparentlens or cover layer 302 is provided. A viewing area within thetouchscreen unit can be observed through the cover layer 302, while thecover layer 302 protects the touchscreen unit 300 from physical damage.Moreover, in various embodiments extremely robust, scratch-resistant,and substantially transparent materials are employed, such as sapphireglass which is a synthetically produced crystal that is well-suited foruse in touchscreens. In various alternate embodiments, the cover layer302 is made of Gorilla Glass™ from Corning Incorporated from Corning,N.Y.

In various embodiments, a common base layer 304 is provided immediatelybeneath the cover layer 302. In various embodiments, an air gap betweenthe cover layer 302 and the common base layer 304 is filled with asubstantially transparent optical bonding agent. It is understood thatthe cover layer can be arbitrarily thin, integral to, and forming a partof the common base layer 304. In an embodiment, the common base layer304 includes a touch sensor 312 that can be used to sense touch at thesurface of the touchscreen unit 300. In various embodiments, the commonbase layer 304 is made of borosilicate glass. In an embodiment, thetouch sensor is a capacitive touch panel (“CTP”) made of a transparentconductive material such as indium tin oxide (“ITO”) patterned in anarray upon the upper face of the common base layer 304 and, in variousembodiments, further processed to facilitate the electricalinterconnections.

In various embodiments, the bottom face of the common base layer 304includes materials which provide it with photovoltaic properties. Invarious embodiments, a photovoltaic surface 316 (as shown in FIGS. 8 and9 ) is made up of an exterior portion 308 and an interior portion 310.The photovoltaic surface 316 is the surface of the common base layer 304to which the interior portion 308 is applied. In an embodiment, theexterior portion 308 is substantially continuous, meaning that theexterior portion 308 is substantially intact and not etched. Bycontrast, in various embodiments, the interior portion 310 isphotoetched away (as further described in reference to FIGS. 5A-5B, 6 ,and 7 described below) so that only a minor portion of the interiorportion 310 actually covers the surface of the common base layer 304.

In some embodiments, display module 306 is provided beneath the commonbase layer 304. In various embodiments, the display module 306 is aliquid crystal pixel array having a pixel pitch of 126.9 micrometer witheach pixel being made up of 9 apertures, 3 apertures for each colorsub-pixel. In an embodiment, there is 5 micrometer gap between theapertures. In various embodiments, it is possible to superimpose 10micrometer wide strips of photovoltaic material such that only 10% ofthe area of the display module 306 is blocked and the brightness andcontrast of the display is only minimally impacted. In an embodiment,the strips of photovoltaic material are superimposed over the columns ofthe display pixels at a 25-degree tilt angle resulting in a minimalMoire consequence.

In various embodiments, the composite photovoltaic surface 316, which ismade up of the exterior portion 308 and the interior portion 310, iscircular or substantially congruent to the shape of the face of thesmartwatch 100 or other portable electronic device. The photovoltaicsurface is further shown in FIGS. 8 and 9 below. In various embodiments,the exterior portion 308 is made up of an annular ring of substantiallycontinuous photovoltaic material along the distal perimeter of thedisplay. Further, the interior portion 310 of photovoltaic material maybe dispersed in a pattern across the interior portion 310 of the commonbase layer 304 so as to minimally obscure viewing of a viewing areawithin the touchscreen unit 300. The photovoltaic surface 316 ispositioned on the bottom face of the common base layer 304 between thedisplay module 306 and the common base layer 304. The touch sensor 312is deposited upon the upper face of the common base layer 304. Invarious embodiments, a backlight 314 is provided so the display module306 is visible in dark or relatively low-light environments.

Photovoltaic Cells

In some embodiments, the photovoltaic cells may be provided on thephotovoltaic surface 316. The photovoltaic surface 316 may be disposedon the bottom face of the common base layer 304 between the displaymodule 306 and the common base layer 304. Various embodiments of thephotovoltaic cells and the photovoltaic cell configurations are providedin FIGS. 5A-9 .

In configurations of the present invention, a photovoltaic stack may beprovided in which the width of a metal electrode is less than the widthof absorber (e.g., PIN and AZO) layers. As the metal electrode islargely responsible for the lack of transparency in the stack,increasing the width of the absorber layers in comparison to the widthof the metal electrode improves energy performance while providingsimilar, or even better, optical visibility. That is, the appearance ofa substantially transparent photovoltaic cell may be improved bydecreasing the width of the metal electrode without decreasing the widthof the absorber layer(s). This configuration may be used withsingle-cell photovoltaic implementations or with multi-cell photovoltaicimplementations. In multi-cell implementations, some cells may employ astandard configuration where the widths of the various layers aregenerally equal, while other cells may employ the improved design wherethe width(s) of the absorber layer(s) are wider than the width of themetal electrode. To provide high efficiency between the cells, the cellsmay be electrically connected in series. In some embodiments, themulti-cell design may provide for the various photovoltaic cells to beconnected in parallel. Consequently, when a photovoltaic cell is notreceiving electromagnetic radiation, the other photovoltaic cells maystill generate power. Such mixed usage allows the device to present anycombination of desired performance and appearance.

FIG. 4 depicts a table presenting various photovoltaic cells generallyreferenced by the numeral 400. The various configurations of thephotovoltaic cells comprise three designs, a standard design 402, afirst design 404, and a second design 406. The photovoltaic cells mayutilize a metal layer 408 which in some embodiments, may be an opaque orsomewhat opaque metal electrode in combination with semi-transparentabsorber layers comprising PIN/AZO or the like.

In some embodiments, the standard design 402 comprises a metal layer408, a PIN layer 410, and an AZO layer 412. In some embodiments, the PINlayer 410 and the AZO layer 412 may generally be referenced as absorberlayers. In standard configurations, shown by the standard design 402,the width of each layer (metal layer 408, PIN layer 410, AZO layer 412)is substantially the same. Here, the exemplary width of 10 micrometersis shown.

In some embodiments, the metal layer 408 may comprise the electrode formoving current from the absorber layers to the electrical components ofthe electronic device. The metal layer 408 may comprise any conductivematerial such as, for example, aluminum, molybdenum, copper, zinc,nickel, graphite, carbon, titanium, brass, silver, gold, platinum andpalladium, mixed metal oxide, and any alloy or combination thereof. Thevisibly restrictive metal electrode may be disposed on the absorberlayers comprising the PIN layer 410 and the AZO layer 412.

In some embodiments, the absorber layers comprise the PIN layer 410 andthe AZO layer 412. In some embodiments, the PIN layer 410 may comprisean amorphous silicon, a microcrystalline silicon, perovskites, or anyother PV chemistries. The PIN layer provides a PIN junction forgenerating an electrical field with p-type and n-type regions with anintrinsic layer between. Any typical PIN junction may be used inembodiments described herein. In some embodiments, the AZO layer 412comprises aluminum-doped zinc oxide. Though AZO is described inembodiments herein, any transparent or semi-transparent conductive oxidefilm such as for example, indium and tin oxides may be used. Further,any organic, inorganic, and polymer may be used.

As shown in the standard design 402, the width of all layers (i.e.,metal layer 408, PIN layer 410, and AZO layer 412) are substantially thesame. The exemplary width of the three layers shown is 10 micrometers.However, any width may be used. As described above the metal layer 408may be opaque, reflective, translucent, or provide visual obstructionsuch that visibility through the metal layer 408 to the display below isrestricted. Reducing the width of the metal layer 408 increasesvisibility to the display disposed below the metal layer 408. Theexemplary first design 404 is also presented in FIG. 4 . The firstdesign 404 presents the metal layer 408 as narrower than the absorberlayers to increase visibility. The width of the metal layer 408 as shownis 10 micrometers and the width of the absorber layers is 12micrometers. In some embodiments, the width of the metal layer may be 10micrometers and the absorber layers may be 14 micrometers. These widthsare exemplary, and any widths may be used. The width difference betweenthe metal layer 408 and the absorber layers may be any ratio that bothincreases visibility and provides efficient energy production.

In some embodiments, the width of the metal layer 408 may be optimizedbased on visibility and efficiency. The narrower the metal layer 408 thehigher visibility beyond the metal layer 408 to the display below.Therefore, for aesthetic purposes, it may be desirable to have the metallayer 408 as narrow as possible. However, the metal layer 408 is aconductor and the narrower the metal layer 408, the higher theelectrical resistance. If the metal layer 408 is too narrow, the metallayer 408 may heat up, thereby experiencing thermal stress, and evenpotential failure. Therefore, there is a trade-off between visibilityand efficiency of the photovoltaic cells.

Further, the width of absorber layers provides various efficienciesbased on the width that must be taken into account when changing thewidth of the metal layer 408. The absorber layers may begin to loseefficiency at due to the width of the absorber without metal. However,the second design described below resolves this issue. Consequently, thepermissible widths of absorber layers also are constrained. Absorberlayer width test results are provided in the table below.

Active area (cm²) Power (1sun) Win Power (%) absorber 10 μm 2.12E−0418.90 absorber 11 μm 2.21E−04 19.69  4% absorber 12 μm 2.29E−04 20.47 8% absorber 13 μm 2.38E−04 21.24 12% absorber 14 μm 2.47E−04 22.02 16%absorber 15 μm 2.55E−04 22.78 21%

A width ratio between the metal layer 408 and the absorber layers may beoptimized based on a desired visibility and the efficiency of thephotovoltaic cell. For example, the layers may be optimizedsimultaneously. The metal layer 408 width may be optimized based onvisibility and efficiency and the absorber layer 416 may be optimizedbased on efficiency. The optimization may be performed simultaneouslysuch that any effects from changes to the metal layer 408 on theabsorber layers and vice versa may be captured. In some embodiments, themetal layer 408 width is 10 micrometers, and the width of the absorberlayers is approximately 14 micrometers. In some embodiments metal layerwidth is between 3 and 11 micrometers and the absorber layer is between9 and 31 micrometers. Any width combination may be determined throughthe optimization analysis and may be applied to the first design 404 andthe second design 406.

Any varying combination of widths may be utilized that achieve thedesired balance of energy performance and visibility. In onecombination, the absorber layers (PIN/AZO) are provided a width of about13 μm while the metal electrode presents a width of 10 micrometers. Sucha configuration provides a power gain of about 14% without substantiallydecreasing display visibility. In some embodiments, two lithographymasks may be employed to deposit the layers (a first mask for the metalelectrode, a second for the absorber layer(s)) to enable theconfigurations described herein. The lithography masking and etchingprocess for producing the various photovoltaic cells is shown in FIGS.5A-5B and described in detail below.

The second design 406 also comprises the metal layer 408 and theabsorber layers. Here, the absorber layer 416 may include both PIN andAZO or just PIN as a front contact is provided in a TransparentConductive Oxide (TCO) layer 418 that may comprise AZO. The TCO layer418 may provide additional electrode layers for greater efficiency. Insome embodiments, a reflective material may be provided on a side of theTCO layer 418 opposite the incoming electromagnetic radiation to reflectthe electromagnetic radiation back through the absorber layers tofurther increase efficiency. The second design also comprises an IndiumTin Oxide (ITO) layer 414 disposed between the metal layer 408 and theabsorber layer 416.

In some embodiments, the ITO layer 414 comprises a patterned array toprovide a capacitive touch sensor or capacitive touch panel (CTP) asdescribed herein. The ITO layer 414 may be indium tin oxide or any otherconductive oxide, organic, inorganic, or any other material that may beused as a CTP. The ITO layer 414 may be disposed at or near a topportion of the common base layer 304 and be electrically interconnectedto provide touchscreen capabilities. The ITO layer 414 may detectvariations in capacitance near the ITO layer 414. The ITO layer 414 maybe the same width as the absorber layers. The ITO layer 414 is furtherdescribed in embodiments below. Further, the TCO layer 418 may be thefront contact provided by the AZO layer 412 as described above. In someembodiments, the TCO layer 418 may be the AZO layer 412. The layers ofthe second design 406 may be masked and etched using the lithographytechniques described below.

FIGS. 5A-5B depict an exemplary process for etching layers for producingthe photovoltaic cells generally referenced by the numeral 500. Thesteps 502 are presented for the typical process 504 that may result inthe standard design 402, the first design process 506, and the seconddesign process 508. Prior to the etching process, the various layers arestacked. For example, the standard design 402 and the first design 404comprise the metal layer 408, the PIN layer 410, and the AZO layer 412.The second design 406 comprises the metal layer 408, the ITO layer 414,the absorber layer 416, and the TCO layer 418 where, in someembodiments, the absorber layer 416 may be the PIN layer 410 and the TCOlayer 418 may be the AZO layer 412.

At step 510, a first lithography mask is provided for etching. Aphotoresistive material is provided on the photovoltaic cells to maskthe portions of material that require no etching. Here, thephotoresistive material is substantially the width of the desired widthof the metal layer 408 after etching. Therefore, the material that ismasked by the photoresistive material is not removed. During the etchingprocess the material that is not masked is removed and only the materialthat is masked remains. When the photoresistive material is in place,the process moves to step 512.

At step 512, the back contact material is etched. In this case, the backcontact material is the metal layer 408. In the standard design 402, themetal layer 408 is etched to a width that will also be provided to theabsorber layers. The first design 404 and the second design 406 may beetched to a width based on the width optimization described above. Insome embodiments, the metal layer 408 of the first design 404 and thesecond design 406 may be different from the standard design 402. Anycombination of widths of the metal layer 408 and the absorber layers maybe provided on the various photovoltaic cells. At this point, theetching of the second design process 508 is finished. The width of themetal layer 408 is etched to the desired width and the subsequent layersare left.

At step 514, a second etching process is provided with the samephotoresistive mask placement as above. The standard design 402 is theonly design where the PIN layer 410 is the same width as the metal layer408. As such, the second etching process with the same widthphotoresistive mask as the first etching is only applied to the standarddesign 402.

At step 516, a stripping operation is performed of the lithography mask1 from the standard design 402, the first design 404, and the seconddesign 406, to expose the metal layer 408 and the PIN layer 410. At thispoint, the typical process 504 to create the standard design 402 iscomplete. The metal layer 408 and the PIN layer 410 were both etched tothe same width. The first design process 506 and the second designprocess 508 continue on FIG. 5B and described below.

At step 518, lithography mask 2 is applied to the first design 404 andthe second design 406. The photoresistive mask is applied over and tothe sides of the metal layer 408 to protect the metal layer 408 and thecovered sections of the PIN layer 410 from etching. The PIN layer 410 ismasked to provide a width greater than the width of the metal layer 408.Next, at step 520, the first design 404 is etched. The photoresistivemask blocks the photoetching and the unblocked portion of the PIN layer410 is removed.

Further at step 520 the ITO layer 414 and absorber layer 416 may beremoved using chemical products. The ITO layer 414 may be removed firstwith a first chemical. The absorber layer 416 may be removed second witha second chemical. In some embodiments, masks may be provided to protectthe materials that are not etched from the first and second chemicalsduring the etching process. At step 522, the lithography masks arestripped revealing the final result.

At step 524, the final results are presented. The final result of thetypical process 504 is the standard design 402 where the metal layer 408is substantially the same width as the absorber layers. This provides ahighly efficient power generation process with a low display visibilityrelative to the other processes. The final result of the first designprocess 506 is the first design 404. As described above, the firstdesign 404 presents the metal layer 408 width narrower than the absorberlayers. The first design 404 results in a higher display visibility withan increase in efficiency or at least without a substantial loss inefficiency. The trade-off between visibility and efficiency may beoptimized as described above. The second design process 508 results inthe second design 406. The second design 406 presents the metal layer408 width narrower than the absorber layers width with the ITO layer 414disposed between.

In some embodiments, the photovoltaic cells may be providedindependently of any electronic device. The photovoltaic cells may beconfigured in an array with a pin out for connecting to a printedcircuit board PCB or may be provided with a PCB that may be compatiblewith charging any energy storage device. As such, the photovoltaic cellsmay be generic to any electronic device such that the photovoltaic cellsmay be adaptable to connecting to, and powering, various electronicdevices.

FIGS. 6 and 7 illustrate a touch sensor 312 on a front face of thecommon base layer 304, in accordance with various embodiments of thepresent disclosure with a flexible printed circuit cable 602 generallyreferenced by the numeral 600 and without the flexible printed circuitcable 602 generally reference by the numeral 700. In various embodimentsthe touchscreen aspect of the portable electronic device is provided asby means of the CTP made up of the ITO array on the upper surface of thecommon base layer 304 shown in FIG. 6 . Additionally, a flexible printedcircuit cable 602 is provided with connector 604 that can be connectedto electronics associated with the smartwatch 100 such as theperformance monitoring component 204 as shown in FIG. 2 .

In various embodiments, contact pads made from ITO are provided on theglass surface for electrically interconnecting with the flexible printedcircuit cable 602. In various embodiments, contact pads 802 made ofplated copper are provided on the flexible printed circuit cable 602 tofacilitate this electrical interconnection. In various embodiments,anisotropic conductive film (“ACF”) material which acts like aconductive glue is provided to bond the glass to the flexible printedcircuit cable 602. In various embodiments, the CTP array works bysensing differences in capacitance between the ITO areas of the touchsensor 312 of FIGS. 6 and 7 . The flexible printed circuit cable 602includes the connector 604 in such a way that the flexible printedcircuit cable 602 can conveniently be folded under the common base layer304 and plugged into the electronics of the smartwatch 100 before thehousing 102 (of FIG. 1 ) is sealed closed. In various embodiments, theCTP of the top face of the common base layer 304 is either affixed tothe cover layer 302 or in very close proximity. In order to improvecapacitive touch sensitivity, the distance between the ITO touch sensor(the indium tin oxide pattern on the glass) and the touching objectbeing sensed (e.g., a human finger) is minimized. Additionally,sensitivity is enhanced by minimizing a dielectric constant of thematerials in that gap. In various embodiments, for a wearableapplication such as the smartwatch 100, the touch sensor 312 can sensethrough air gaps between a lens or similar cover layer 302. It isunderstood that the touch sensor 312 operates sub-optimally throughlayers that are conductive or hold an electrical charge. Where anelectrical charge builds up on the cover layer 302, with for example anadditional anti-glare coating (not shown), the touch sensor 312 may failto operate properly when exposed to direct sunlight, for which reason,consistent with the present teachings, materials are selected that donot hold a substantial electrical charge.

As described above, capacitive touch sensitivity is increased byminimizing the dielectric constant of the combination of materialsbetween the touch sensor 312 and the object being sensed (typically afinger). By way of reference the dielectric constant of ambient air isapproximately 1.0 (relative permittivity), while sapphire is about 10and glass is about 5, with conductive metals having a dielectricconstant that is basically infinite. Accordingly, it is understood that,while glass, such as borosilicate glass, allows for greater touchsensitivity than some harder materials, it lacks the protectivequalities of sapphire. Accordingly, a material for cover layer 302 isselected to provide the most physical protection while still providingadequate touch sensitivity. In this way, a position at which a finger orother capacitive pointing device touches the surface of the cover layer302 can be accurately determined by changes in the capacitance measuredin the ITO pattern and transmitted to various pins of a connector 604.

FIGS. 8 and 9 illustrate the photovoltaic surface 316 on a front face ofthe common base layer 304, in accordance with various embodiments of thepresent disclosure. In various embodiments, the photovoltaic surface 316is formed from one or more layers of doped amorphous silicon which hasthe advantages of low cost as well as low toxicity compared to someother photovoltaic materials, but it is understood that otherphotovoltaic materials may be employed without departing from thepresent teachings. In various embodiments the pattern of the interiorportion 310 of the photovoltaic surface 316 is formed by firstdepositing a substantially uniform layer or layers of photovoltaicmaterial and then removing desired portions of the material by way ofphotoetching as described above in FIGS. 5A-5B.

In various embodiments, photovoltaic energy is transmitted through thecover layer 302 and the ITO array of touch sensor 312 (as well as thecommon base layer 304) into the photovoltaic layer. The photovoltaiclayer is made up of the exterior portion 308 and the interior portion310 of the photovoltaic surface 316 comprising the photovoltaic cells.The photovoltaic cells then generate electrical current and, therefore,energy in the photovoltaic layer which is then collected by way ofconductors at tab 702 and through the flexible printed circuit cable 602to be stored in an energy storage device as described in connection withthe battery 212 of FIG. 2 . Tab 702 is bonded to the common base layer304 with ACF to provide an electrical interconnection to the flexibleprinted circuit cable 602. In some embodiments, the photoelectric cellsprovided on the photovoltaic surface may be any of the above-describedphotovoltaic cell designs. The photovoltaic cells may be any one orcombination of the standard design 402, the first design 404, and thesecond design 406.

Although the invention has been described with reference to theembodiments illustrated in the attached drawing figures, it is notedthat equivalents may be employed, and substitutions made herein withoutdeparting from the scope of the invention as recited in the claims.

Having thus described various embodiments of the invention, what is claimed as new and desired to be protected by Letters Patent includes the following:
 1. A photovoltaic power system for an electronic device, the photovoltaic power system comprising: a capacitive touch panel comprising an indium tin oxide array configured to detect variations in capacitance; and at least one photovoltaic cell comprising: a first layer comprising a first conductive electrode; and a second layer electrically connected to the first layer and configured to generate electrical current when exposed to electromagnetic radiation; and a third layer comprising a second conductive electrode, wherein a first layer width is less than a second layer width; and wherein the capacitive touch panel is disposed above the first layer.
 2. The photovoltaic power system of claim 1, wherein the first layer width is between four and ten micrometers, wherein the second layer width is between ten and fifteen micrometers, and wherein the first conductive electrode comprises at least one of microcrystalline silicon, amorphous silicon, and perovskites for generating the electrical current.
 3. The photovoltaic power system of claim 1, wherein the first layer width is ten micrometers, and wherein the second layer width is fourteen micrometers.
 4. The photovoltaic power system of claim 1, wherein the first layer width is seven micrometers, and wherein the second layer width is ten micrometers.
 5. The photovoltaic power system of claim 1, wherein the at least one photovoltaic cell is a first photovoltaic cell; and further comprising a second photovoltaic cell comprising: a third layer comprising a second metal electrode; and a fourth layer electrically connected to the third layer and configured to generate electrical current when exposed to electromagnetic radiation, wherein a third layer width is greater than the first layer width, and wherein the first photovoltaic cell and the second photovoltaic cell are electrically connected in series.
 6. The photovoltaic power system for claim 1, further comprising: an interior portion comprising the at least one photovoltaic cell; and an exterior portion comprising an exterior photovoltaic cell disposed around an outer edge of the interior portion.
 7. The photovoltaic power system of claim 1, wherein the photovoltaic power system is configured to be connected to and provide power to at least one of a wearable and a handheld electric device.
 8. A photovoltaic power system for an electronic device, the photovoltaic power system comprising: a capacitive touch sensor comprising an indium tin oxide array configured to detect variations in capacitance; and a base layer comprising: a touch sensor; at least one photovoltaic cell comprising: a first layer comprising a first conductive electrode; and a second layer electrically connected to the first layer and configured to generate electrical current when exposed to electromagnetic radiation; and a third layer comprising a second conductive electrode, wherein a first layer width is less than a second layer width; and wherein the capacitive touch sensor is disposed above the first layer.
 9. The photovoltaic power system of claim 8, wherein the second layer width is between ten and fifteen micrometers, and wherein the first layer width is between four and ten micrometers.
 10. The photovoltaic power system of claim 8, wherein the first layer width is seven micrometers, and wherein the second layer width is ten micrometers.
 11. The photovoltaic power system for claim 8, further comprising: an interior portion comprising the at least one photovoltaic cell and a second photovoltaic cell, wherein the second photovoltaic cell comprises a metal electrode layer comprising a width greater than the first layer width; and an exterior portion comprising at least one exterior photovoltaic cell disposed around an outer edge of the interior portion.
 12. The photovoltaic power system of claim 8, wherein the base layer is configured to be disposed above a liquid-crystal display and patterned to provide minimal visual obstruction of the liquid-crystal display.
 13. The photovoltaic power system of claim 8, wherein the first conductive electrode comprises at least one of microcrystalline silicon, amorphous silicon, and perovskite for generating the electrical current. 